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Stellar activity cycles in a model for magnetic flux generation and transport

Published online by Cambridge University Press:  05 July 2012

Emre Işik
Emre Işik*
Affiliation:
Department of Physics, Faculty of Science & Letters, Istanbul Kültür University34156, Bakırköy, Istanbul, Turkey email: e.isik@iku.edu.tr
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Abstract

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We present results from a model for magnetic flux generation and transport in cool stars and a qualitative comparison of models with observations. The method combines an αΩ-type dynamo at the base of the convection zone, buoyant rise of magnetic flux tubes, and a surface flux transport model. Based on a reference model for the Sun, numerical simulations were carried out for model convection zones of G- and K-type main sequence and subgiant stars. We investigate magnetic cycle properties for stars with different rotation periods, convection zone depths, and dynamo strengths. For a Sun-like star with Prot=9 d, we find that a cyclic dynamo can underly an apparently non-cyclic, ‘flat’ surface activity, as observed in some stars. For a subgiant K1 star with Prot=2.8 d the long-term activity variations resemble the multi-periodic cycles observed in V711 Tau, owing to high-latitude flux emergence, weak transport effects and stochastic processes of flux emergence.

Keywords

stars: activitystars: interiorsstars: magnetic fields(magnetohydrodynamics:) MHDSun: interiorSun: magnetic fields
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 7 , Symposium S286: Comparative Magnetic Minima: Characterizing quiet times in the Sun and Stars , October 2011 , pp. 291 - 295
Copyright
Copyright © International Astronomical Union 2012

References

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